Operating dynamo-electric machines



No. 625,806. Patented May 30, I899.

E. w. RICE, In. OPERATING DYNAMO ELECTRIC MACHINES.

(Application filed m. 1, 1897.)

(In llodel.)

\AATPIESEEE.

I UNITED STATES PATENT OFFICE.

ED\VIN IV. RICE, JR, OF SOHENECTADY,NEWV YORK, ASSIGNOR TO THE GENERALELECTRIC COMPANY, OF NEW YORK.

OPERATING 'DYNAMO-ELECTRIO MACHlNES.

SPECIFICATION forming part of Letters Patent No. 625,806, dated May 30,1899.

Application filed March 1, 1897.

To all whom it may concern.-

Be it known that I, EDWIN W. RICE, J r., a citizen of the United States,residing at Schenectady, in the county of Schenectady, State of NewYork, have invented certain new and useful Improvements in OperatingDynamo- Electric Machines, (Case No. 536,) of which the following is aspecification.

My invention relates to dynamo-electric machines, and has for its objectto provide for such machines a device which will equalize the wear uponthe collecting arrangements, so that the commutators or collectors maybe kept true, require less turning and manipulation to make them run,and prevent their sparking or undue wear.

In the operation of dynamos it is found desirable to keep the collectingdevices, particularly the rotary portions, as true as possible, so thatthe brushes may not jump and cause sparking and so that the turning downof the collector may be avoided. While this is the case with theordinary collecting-rings applied to alternators, it is not so materialwith them, they being comparatively simple devices and there being nodifference of potential to cause a spark if the brush makes imperfectcontact; but it is of more importance with commutators and moreespecially with the large and costly commutators of modern dynamos. Insuch devices Where many brushes are employed and the brushes track, sothat all of the brushes occupying the same relative position follow thesame lines around its periphery, the commutator is apt to wear ingrooves with ridges between them, though these are not very high. Stillif by the end play of the armature (which is unavoidable and for somereasons desirable) these grooves and the brushes do not coincide thebrush becomes heated and sparks and gives rise to the well-knowndifficulties caused by such incidents. To avoid these troubles, Ipreferably cause the armature to shift back and forth in its bearings orto have a little more than the usual amount of end play; but instead ofthis being a casual incident of the operation of the machine caused bythe slightly-imperfect balance of the armature or other mechanicalreasons I so arrange it that it shall be a regular reciprocation of thear- Serial No. 625.467. (No model.)

mature-shaft in its bearings, so that the brusheswill rub over theentire surface of the commutator. To accomplish this, I arrange outsidethe end of the shaft an electromagnet with a source of current incircuit therewith and bya suitable make-and-break device of any properform energize the magnet from time to time, so that it exerts a pull onthe shaft. This energization being intermittent, the shaft tends toreciprocate in its bearings.

The accompanying drawings show an em= bodiment of my invention in aparticular way.

Figure 1 is a diagrammatic elevation of the invention applied to tworotary converters, while Fig. 2 is an enlarged detail, and Fig. 3 is amodification.

It is manifest that the device is equally applicable to all classes ofdynamo-electric machinery, and I have simply illustrated the rotaryconverters because they happen to be the machines to which I have firstapplied it.

In Fig. 1,.A A are the dynamos, B B the alternating-current mainsleading from one side of the armature, and G O the continuouscurrentmains leading from the commutators C O. I have illustrated a single setof positive and negative brushes; but it is to be understood that asuitable number, in accordance with the number of field-poles and thearmature'connectious, will be employed. D is a separate source ofcurrent, which I have represented in diagram as a small dynamo; but anyother suitable source might be used. In dotted lines I have indicatedthat ashuntcircuit to the main continuous-current circuit might beemployed. Ordinarily this would not be desirable on account of the highvoltage andthe difiiculty of breaking the circuit; but (particularlywith small machines) it might be employed. At E is a commutating device,an ordinary make-and-break arrangement, in. which insulation andconducting portions alternate in a way Well understood. The commutatoris shown as rotated from the shaft of the main machine, and the lengthof the breaks and consequent length of the periods during which currentis transmitted to the shifting device is to be proportioned to theeffect desired and to the size of the machine, 820., in ways Wellunderstood. F F are the mains or leads going to the shifting devices GG.

Fig. 2 shows in enlarged form one of the bearings K of the convertershaving the device applied to it. In this I is the shaft, thereciprocation of which is to be attained by the device G, which consistsof an iron core with a coil H surrounding it, the coil being connectedto the mains F. Insulating-bushings g are provided. The rest of thebearing is of -a form well understood. Forming no special part of myinvention, it will therefore not be particularly described.

The invention is particularly applicable to the rotary converters whichI have shown, because with such machines, they being driven by thecurrent, there are no mechanical reasons why the armature would shift inits bearings, there being no belt or other intermitten tly-appliedmechanical force, the armature therefore tending to keep in the magneticcenter of the field. For the same reason my invention is particularlyapplicable diameter as the end of the shaft I, and the magnetic circuitis as indicated by the dotted lines instead of being through the bearingK. This construction gives a very strong pull when energized on accountof the shortness of the magnetic circuit.

That I claim as new, and desire to secure by Letters Patent of theUnited States, is-

1. The combination of a shaft and an ironclad magnetizing-coil mountedin inductive proximity to the end of said shaft.

2. The combination of a shaft and an annular magnetizing-coil mounted ininductive relation to the end of said shaft and with its axissubstantially coincident with that of the shaft.

3. The combination of a shaft carrying the rotating member of adynamo-electric machine, and aniron-clad, annular magnetizingcoilmounted in inductive relation to the end of said shaft and with its axissubstantially coincident with that of the shaft.

4. In an end-play device for rotary convert- I ers, the combination withthe shaft of the rotary converter, of an iron-clad, annularmagnetizing-coil mounted in inductive relation to the end of said shaftand with its axis substantially coincident with that of the shaft, andmeans for passing a magnetizing-current through said coil and forvarying the value of said magnetizing-current.

In witness whereof I have hereunto set my hand this 25th day ofFebruary, 1897.

EDIVIN IV. RICE, JR. IVitnesses:

B. B. HULL, C. L. HAYNES.

